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How to export mass and stiffness matrices of a large model?

JohLut
Hi,
 
up to now, I've applied the command EXTSEOUT (STIFFNESS MASS ASMBULK EXTID = 10 DMIGPCH) to get the matrices as a byproduct of the superelement reduction process.
This is ok for models of moderate size.
 
However, this approach seems not reasonable for rather large models (~1.000.000 nodes) as the intermediate files like *.DBALL are blown up to more than 16 GB and the computations take ages.
 
Since I'm not interested in the external superelement itself I'm wondering if there might be a simpler way to export the system matrices without extensive reduction computations.
 
Best regards,
Johannes
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  • 0
    Did you try using the SPARSE op4 option? Instead of a positive IUNIT value, use a negative IUNIT and it should write sparse format. Use the DMAP Programmers Guide to see how the OUTPUT4 module operates. The resulting file size can actually be larger if there aren't many imbedded zeros.
     
    For example, the following writes to Fortran unit 35:
     
    output4 KAA,MAA,,,//0/35///15 $ non-sparse
    output4 KAA,MAA,,,//0/-35///15 $ sparse
     
    Also, the DIGITS entry on the OUTPUT4 statement can be changed for less precision… in the example above, it is using 15 but the default is 9... this would reduce the file size.
     
    For example:
    DIGITS = 9, then the format will be 1P,5E16.9
    or if DIGITS = 15, then the format will be 1P,3E22.15
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  • 0
    Did you try using the SPARSE op4 option? Instead of a positive IUNIT value, use a negative IUNIT and it should write sparse format. Use the DMAP Programmers Guide to see how the OUTPUT4 module operates. The resulting file size can actually be larger if there aren't many imbedded zeros.
     
    For example, the following writes to Fortran unit 35:
     
    output4 KAA,MAA,,,//0/35///15 $ non-sparse
    output4 KAA,MAA,,,//0/-35///15 $ sparse
     
    Also, the DIGITS entry on the OUTPUT4 statement can be changed for less precision… in the example above, it is using 15 but the default is 9... this would reduce the file size.
     
    For example:
    DIGITS = 9, then the format will be 1P,5E16.9
    or if DIGITS = 15, then the format will be 1P,3E22.15
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